1. Field of the Invention
The present invention relates to an image formation apparatus such as a copier or laser printer, for example, which employs electrophotography, and particularly relates to an image formation apparatus and a control method thereof, having multiple cartridges each of which comprises at least one component of an image formation unit, and is detachably configured, in the main unit of the color image formation apparatus.
2. Description of the Related Art
Conventional color image formation apparatuses which can detachably mount multiple developing agent storage cartridges have been known. FIG. 9 illustrates a rotary-type image formation apparatus which has been conventionally known, and which detachably and rotatably holds multiple developing agent storage cartridges. With this method, image formation is performed by a cartridge holding unit disposing one of multiple developer storage cartridges at a image formation position.
With the rotary-type color printer shown in FIG. 9, a photosensitive drum 10, which is a image carrying member, is driven in the direction of the arrow shown in the drawing by a driving means not shown, and is uniformly charged by a first charging device 20. Next, a laser beam L generated according to yellow image patterns is cast on the photosensitive drum 10 by an exposure device 30, and a latent image is formed on the photosensitive drum 10. In the event that the photosensitive drum 10 moves further in the direction of the arrow, of the process cartridges 40a, 40b, 40c, and 40d, which are held by a rotational supporting member 110, the cartridge 40a containing yellow toner, for example, is rotated so as to face the photosensitive drum 10. The electrostatic latent image on the photosensitive drum 10 is then manifested by yellow toner in the selected process cartridge 40a. An intermediate transfer belt 50 rotates at generally the same speed as the photosensitive drum 10 in the direction of the arrow, and performs primary transfer of a toner image, which has been formed and is carried by the photosensitive drum 10, onto the outer circumference of the intermediate transfer belt 50, by the first transferring bias voltage applied to a first transferring roller 80a. The above processing is performed for multiple colors, i.e., yellow, magenta, cyan, and black, thereby forming a toner image in multiple colors on the intermediate transfer belt 50. Next, a recording medium is supplied by a pickup roller 130 from a recording medium cassette 120 at a predetermined timing. At the same time, a second transferring bias voltage is applied to a second transferring roller 80b, and the toner image is transferred from the intermediate transfer belt 50 to the transferring member.
Moreover, the transferring member is transported to a fixing unit 60 by a transporting belt 140, and is fixed by melting, thereby obtaining a color image. Also, the residual toner on the intermediate transfer belt 50 is charged by an intermediate transferring cleaning roller 150, and is reverse-transferred onto the photosensitive drum at the next time for primary transfer. On the other hand, the residual toner following transferring on the photosensitive drum 1 is cleaned up by a cleaning device 70.
Here, each of the process cartridges 40a, 40b, 40c, and 40d, integrally comprise toner, a developing roller, developing plate, and so forth, and are detachably mounted with regard to the printer body. Also, NV (Non-Volatile) RAM 41a, 41b, 41c, and 41d, are provided on the sides of the cartridges as non-volatile storage units for storing information regarding the process cartridge or the like. Also, a reading/writing means 42 is provided at a position so as to face or contact one of the NVRAM 41a, 41b, 41c, or 41d, which faces the photosensitive drum 10 at the position P0. Reading/writing of information stored in the NVRAM is performed at a timing such as at the timing of turning on the power supply, the timing after printing of a predetermined number of sheets, or the like, and processing wherein image formation conditions are changed, or notice of remaining toner or end of life span and so forth is given to users, is performed corresponding to the information. However, in the event that NVRAM is accessed at such the image formation position (developing position), it is likely that accurate data communication can not be performed due to scattering of toner or influence of the developing voltage.
That is to say, with the rotary-type image formation apparatus, in a case wherein the storage unit such as non-volatile memory or the like is provided at the developing agent storage cartridge so as to manage the life span of the cartridges or the like, it is likely that accurate communication can not be performed due to influence of scattered developer or electric noise due to the developing voltage in the event of accessing the storage unit at the image formation position (developing position).